The evidence of Dean CottleDean Cottle was murder victim Laniet Bain's friend and appeared to have been supportive during her turbulent years leading up to her death. It was alleged he had helped her and lent her his cell-phone to keep in contact with her clients, whilst she worked as a prostitute.
Although he had information he believed might be important in the trial and of value to David Bain’s defence, he disappeared. This information concerned alleged comments by Laniet that she had been sexually abused by her father Robin and was going to confront him in front of the rest of the family, just before the murders. Were such allegations true, they may have provided a motive for Robin Bain to have committed the murders.

Cottle was served with a subpoena to attend court on 29 April 1995 but he failed to appear and an arrest warrant was issued. The subpoena had been served by Defence private investigator Wayne Idour. Cottle appeared before the court voluntarily on 26 May 1995 claiming he had not seen Idour prior to his attendance. He went on say he had contacted police, but was told he was not required at court.

The Bain trial was about to reconvene to hear the Defence’s final address when Justice Williamson was told Cottle had presented himself at court to answer the arrest warrant. Justice Williamson ruled, even at that late stage, that the Defence could call Cottle.

Both counsel questioned him about his failure to appear and about the statement he made to police in June 1994. Cottle was unable to recall details of the conversation with Laniet and his general state was such, that after hearing him, Justice Williamson concluded his evidence was hearsay. He said hearsay is normally excluded because of the well known dangers against which the hearsay rule guards. “Those dangers can be put to one side if the court is satisfied that the evidence, although not in accordance with the rule, is perfectly safe and reliable, or at least reasonably so. I am not so satisfied in this case and accordingly I rule against its admission."

After Bain was sentenced to life imprisonment, Cottle elaborated on his evidence in an affidavit to Defence Counsel Michael Guest, which was used for Bain's appeal. However, the appeal was dismissed as was the appeal to the Privy Council in London.